Continuous Peripheral Nerve Infusions

Overview: 

Background

Almost all peripheral nerve blocks, plexus blocks or fascial plane blocks described can be performed as continuous analgesic techniques. A percutaneously inserted catheter with its tip adjacent to a target nerve, plexus or placed into a fascial plane allows local anesthetic administration over an extended time. 

The advantages of continuous nerve infusions are:

  • Analgesia can be provided for days if desired
  • A block that may be titrated to the desired effect
  • Side effects such as motor weakness can be reduced by rate adjustment.
Clinical Use: 

Peripheral nerve blocks routinely performed as continuous techniques at UCSF are:

  • Adductor canal blocks

This block provides pain control mostly in the distribution of the saphenous nerve. It has shown to provide good pain control in knee surgery including knee arthroplasty. At UCSF, patients presenting for revision knee arthroplasty, an adductor canal catheter is routinely placed for postoperative pain management.

 

  • Popliteal blocks

This block provides pain control provides pain control in the lower leg with the exception of the area innervated by the saphenous nerve. For this reason, the popliteal and the adductor canal block supplement each other perfectly. Popliteal nerve catheters are routinely placed in more complex ankle and foot procedures when increased postoperative pain is expected.

 

  • Interscalene blocks

This block provides pain control following shoulder and upper arm surgery. Placing an interscalene catheter allows longer lasting pain control than a single shot block following more painful procedures.

 

  • Infraclavicular blocks

This block provides pain control following lower arm surgery such as elbow, wrist and hand surgery requiring longer lasting analgesia.

 

  • Erector spinae plane (ESP) blocks

This is a newer block that has been increasingly used as a continuous block in situations when epidural analgesia was contraindicated due to systemic anticoagulation or coagulopathies. Examples include donor hepatectomies and pancreatectomy with isle cell transplant. Evidence for its clinical effectiveness is still sparse. This block is unfortunately clearly inferior to epidural analgesia for these indications. 

Special Considerations: 

Placement of a peripheral nerve catheter is more complex and time consuming than performing a single shot block. 

All inpatients with indwelling catheters require subsequently monitoring and management by the Acute Pain Service.

Catheter migration and disconnections are rare, but are frequently seen, especially once patients start to ambulate.

Continuous peripheral nerve infusions do not maintain blocks that are as dense as single shot blocks. This would require toxic doses of local anesthetic. It is therefore completely normal that the block the day after surgery is 'not as good as it was initially', as patients commonly comment.

Leakage of local anesthetic is not uncommon. In most cases, the catheter still works just fine, as only a small amount of local anesthetic tracks back along the outside of the catheter. In most cases it does not require an intervention. If the leakage is severe, some Histoacryl® and a new Tegaderm® may take care of this problem.

References: 

Ilfeld, Brian M. MD, MS Continuous Peripheral Nerve Blocks: An Update of the Published Evidence and Comparison With Novel, Alternative Analgesic Modalities, Anesthesia & Analgesia: January 2017 - Volume 124 - Issue 1 - p 308-335

Author: 
Matthias Behrends